﻿<p><em>IfcExternalReferenceRelationship</em> is a relationship entity that enables objects from the
<em>IfcResourceObjectSelect</em> to have the ability to be tagged by external references.</p>

<blockquote class="note">
NOTE&nbsp; This relationship is used to assign classification, library or document information to entities that
do not inherit from <em>IfcRoot</em>. It has a similar functionality as the subtypes of <em>IfcRelAssociates</em>.
</blockquote>

<blockquote class="history">
HISTORY&nbsp; New entity in IFC4.
</blockquote>